The present invention relates to methods and apparatus for composing an identification number, which methods and apparatus mitigate against tampering of the identification number once it has been established.
The use of electronic equipment has opened very large and profitable markets in the areas of personal computing, home entertainment, communications, computer networking, transportation, avionics, etc. Indeed, one is pressed to identify a commercial market in which electronic devices do not play a critical role. It is desirable to have the capability of identifying a particular piece of electronic equipment, such as a piece of computing equipment, in order to enjoy security features, tracking (e.g., data mining) features, etc. within the system or systems in which the electronic equipment is utilized. So-called electronic identification (ID) numbers have traditionally been employed for this purpose.
An electronic ID number is conventionally established by way of a plurality of binary values, e.g., logic low (0) values and logic high (1) values, in sequence. Thus, for example, a typical electronic ID number may be expressed as: 00000101.
By way of example, this type of electronic ID number may be utilized to ensure that entities interesting in profiting from the sale of digital content, such as software applications, to end users are not financially harmed by those seeking to pirate such digital content or by those seeking to share such digital content on multiple computing devices. In particular, the computing device of an end user may be equipped with an electronic ID number and the digital content may be distributed to such end users on rewritable storage media. When an end user connects the rewritable storage medium to his or her computing device, the electronic ID number may be used to encrypt the digital content on the rewritable storage medium and overwrite the non-encrypted version of such digital content. When the end user seeks to execute the digital content on his or her computing device, the electronic ID number is used to decrypt the digital content stored on the rewritable storage medium. This system advantageously permits an authorized end user to execute the digital content on his or her computing device, but prohibits using the digital content on some other computing device, which has a different ID number or no ID number at all. Further details concerning this system may be found in U.S. Pat. No. 7,107,461, issued Sep. 21, 2006,the entire disclosure of which is hereby incorporated by reference.
Although systems that take advantage of electronic ID numbers, such as in the example above, will enjoy widespread success as to most end users of electronic equipment, some sophisticated end users may seek to thwart the security, tracking, or other objective by altering one or more electronic ID numbers. The means by which these malefactors alter the electronic ID numbers depends, to a large extent, on how the electronic ID number are implemented. A conventional approach to implementing an electronic ID number includes the use of anti-fuse technology, whereby a shorted anti-fuse element indicates a logic low (0) level and an open (or fused) anti-fuse element indicates a logic high (1) level. Thus, to implement the electronic ID number 00000101, eight anti-fuse elements would be employed, where all such elements would remain shorted except for the first and third elements, which would be fused. Unfortunately, this implementation of the electronic ID number is susceptible to unauthorized modification. Indeed, any of the un-fused elements implementing the ID number may be fused (i.e., opened) to obtain a different electronic ID number. For example, any of the second, and fourth through eighth anti-fuse elements may be fused and, thereby, change any of the logic low (0) values of the electronic ID number to logic high (1) values. Once the electronic ID number has been altered, there would be no way of determining whether unauthorized modification had taken place.
Accordingly, there are needs in the art for methods and apparatus for establishing electronic ID numbers such that the validity of such ID numbers may be determined and unauthorization modification may be detected.